Local skin reactions such as itching, redness and welts may occur when certain individuals who are allergic come in contact with irritants such as perfumes, cosmetics, sunscreens, aerosols, plant products (e.g. poison ivy and poison oak), and latex medical gloves. Topical formulations containing antihistamines and/or corticosteroids are routinely used to treat such allergic reactions, but are not recommended for chronic use and may, themselves, lead to sensitivity reactions.
Several zinc compounds have been used in topical skin formulations, but the results have not, hitherto, been satisfactory. For example, creams containing zinc oxide at high concentrations (20-40 percent by weight) have been used as skin protectants, but tend to create a thick coating which is not readily washable and which is, therefore, uncomfortable to the skin.
Further, compositions containing readily soluble zinc acetate (at 1-2 percent by weight), combined with antihistamine, have been used to prevent local itching when used topically (e.g. "Benadryl Itch Stopping Cream", Warner Wellcome). However, chronic use of such soluble zinc compounds may potentially result in systemic toxicity. Zinc salts have also been used to block adhesion of anti-irritant compounds to the skin, as set forth in PCT/US95/03744, and zinc gluconate gels have been found to exert a soothing effect.